2,079 research outputs found
Evaluation of the Theoretical Uncertainties in the W to Lepton and Neutrino Cross Sections at the LHC
We study the sources of systematic errors in the measurement of the W to
lepton and neutrino cross-sections at the LHC. We consider the systematic
errors in both the total cross-section and acceptance for anticipated
experimental cuts. We include the best available analysis of QCD effects at
NNLO in assessing the effect of higher order corrections and PDF and scale
uncertainties on the theoretical acceptance. In addition, we evaluate the error
due to missing NLO electroweak corrections and propose which MC generators and
computational schemes should be implemented to best simulate the events.Comment: 33 pages, 109 eps figures, uses JHEP3.cls, rotating.sty Version 2
corrects an error in Table 1, adds some references, and updates an author
addres
Determinants Analysis of Organizational Citizenship Behaviors
The purpose of this work is to identify the most representative components and dimensions of the Organizational Citizenship Behaviors within the Moroccan context. The first phase of this paper lies on a theoretical framework defining the individual performance concept, and then we will emphasize the different Organizational Citizenship Behaviors' theories. The method involves an exploratory qualitative inquiry based on directive interviews with executives working in the private companies located in the region of Rabat. The present study reassessed the finding of the existing theories in a purposive sample and in a different context. By identifying the different components of the contextual performance within the Moroccan context we can link several organizational behaviors in the same model, which will pave the way to a confirmatory study. This will allow for more organizationnal consideration of contextual performance and may direct future research on performance management
Systematic Review of Cardiovascular Outcome Trials Using New Antidiabetic Agents in CKD Stratified by Estimated GFR
SALT Long-slit Spectroscopy of Luminous Obscured Quasars: An Upper Limit on the Size of the Narrow-Line Region?
We present spatially resolved long-slit spectroscopy from the Southern
African Large Telescope (SALT) to examine the spatial extent of the narrow-line
regions (NLRs) of a sample of 8 luminous obscured quasars at 0.10 < z < 0.43.
Our results are consistent with an observed shallow slope in the relationship
between NLR size and L_[OIII], which has been interpreted to indicate that NLR
size is limited by the density and ionization state of the NLR gas rather than
the availability of ionizing photons. We also explore how the NLR size scales
with a more direct measure of instantaneous AGN power using mid-IR photometry
from WISE, which probes warm to hot dust near the central black hole and so,
unlike [OIII], does not depend on the properties of the NLR. Using our results
as well as samples from the literature, we obtain a power-law relationship
between NLR size and L_8micron that is significantly steeper than that observed
for NLR size and L_[OIII]. We find that the size of the NLR goes approximately
as L^(1/2)_8micron, as expected from the simple scenario of constant-density
clouds illuminated by a central ionizing source. We further see tentative
evidence for a flattening of the relationship between NLR size and L_8micron at
the high luminosity end, and propose that we are seeing a limiting NLR size of
10 - 20 kpc, beyond which the availability of gas to ionize becomes too low. We
find that L_[OIII] ~ L_8micron^(1.4), consistent with a picture in which the
L_[OIII] is dependent on the volume of the NLR. These results indicate that
high-luminosity quasars have a strong effect in ionizing the available gas in a
galaxy.Comment: 9 Pages, 5 figures, accepted to Ap
Composite Spectral Energy Distributions and Infrared-Optical Colors of Type 1 and Type 2 Quasars
We present observed mid-infrared and optical colors and composite spectral
energy distributions (SEDs) of type 1 (broad-line) and 2 (narrow-line) quasars
selected from Sloan Digital Sky Survey (SDSS) spectroscopy. A significant
fraction of powerful quasars are obscured by dust, and are difficult to detect
in optical photometric or spectroscopic surveys. However these may be more
easily identified on the basis of mid-infrared (MIR) colors and SEDs. Using
samples of SDSS type 1 type 2 matched in redshift and [OIII] luminosity, we
produce composite rest-frame 0.2-15 micron SEDs based on SDSS, UKIDSS, and
Wide-Field Infrared Survey Explorer (WISE) photometry and perform model fits
using simple galaxy and quasar SED templates. The SEDs of type 1 and 2 quasars
are remarkably similar, with the differences explained primarily by the
extinction of the quasar component in the type 2 systems. For both types of
quasar, the flux of the AGN relative to the host galaxy increases with AGN
luminosity (L_[OIII]) and redder observed MIR color, but we find only weak
dependencies of the composite SEDs on mechanical jet power as determined
through radio luminosity. We conclude that luminous quasars can be effectively
selected using simple MIR color criteria similar to those identified previously
(W1-W2 > 0.7 [Vega]), although these criteria miss many heavily obscured
objects. Obscured quasars can be further identified based on optical-IR colors
(for example, (u-W3 [AB]) > 1.4(W1-W2 [Vega])+3.2). These results illustrate
the power of large statistical studies of obscured quasars selected on the
basis of mid-IR and optical photometry.Comment: Accepted for publication in ApJ; 14 pages, 9 figures, 2 tables;
composite Type 1 and Type 2 quasar SEDs available at
http://www.dartmouth.edu/~hickox/Hickox2017_QSO_SED_Table1.tx
Gemini Long-slit Observations of Luminous Obscured Quasars: Further Evidence for an Upper Limit on the Size of the Narrow-Line Region
We examine the spatial extent of the narrow-line regions (NLRs) of a sample
of 30 luminous obscured quasars at observed with spatially
resolved Gemini-N GMOS long-slit spectroscopy. Using the [OIII]
emission feature, we estimate the size of the NLR using a cosmology-independent
measurement: the radius where the surface brightness falls to 10 erg
s cm arcsec. We then explore the effects of atmospheric
seeing on NLR size measurements and conclude that direct measurements of the
NLR size from observed profiles are too large by 0.1 - 0.2 dex on average, as
compared to measurements made to best-fit S\'{e}rsic or Voigt profiles
convolved with the seeing. These data, which span a full order of magnitude in
IR luminosity () also provide strong evidence that there is a flattening of the
relationship between NLR size and AGN luminosity at a seeing-corrected size of
kpc. The objects in this sample have high luminosities which place
them in a previously under-explored portion of the size-luminosity
relationship. These results support the existence of a maximal size of the
narrow-line region around luminous quasars; beyond this size either there is
not enough gas, or the gas is over-ionized and does not produce enough
[OIII] emission.Comment: 10 pages, 6 figures, accepted for publication in the Astrophysical
Journa
A legal study on the right to education of stateless children in Malaysia / Karl Rafiq Nadzarin…[et al.]
This paper is a study done on stateless children and their right to education in Malaysia. Statelessness is a very serious issue in the world today and many governments around the world are learning to deal with this issue. The United Nations various bodies, particularly the United Nations High Commissioner for Refugees have been assisting states around the world on this matter and have been extensively campaigning for general awareness on the issue and problems associated with statelessness. According to the Universal Declaration of Human Rights, every child and person deserves the right to a free education. However, many circumstances prevent this from happening. In Malaysia, this is a problem attributed to many minority communities such as the refugees, asylum seekers and the stateless as the state does not legally recognize the existence of any of these communities. Therefore, they cannot enter local public schools and their rights are not protected. How then is this issue dealt with locally? Or is it ignored completely? Does the state have a legal obligation towards these stateless children with respect to the right to education? This paper will attempt to answer these questions and explore the socio-legal aspects on the subject matter which shall include an analysis of the local and international law, policies and compare it with realities on the ground. Recommendations and suggestions will also be provided to solve this issue with the basic premise of awarding benefit to every party once the right to education is awarded to stateless children in Malaysia
Pediatric asthma attack and home paint exposure
Although asthma mortality has been declining for the past several decades, asthma mor-bidity is on the rise, largely due to deteriorating indoor air quality and comorbidities, such as aller-gies. Consumer products and building materials including paints emit volatile organic compounds (VOCs), such as propylene glycol (PG), which is shown to dehydrate respiratory tracts and can con-tributor to airway remodeling. We hypothesize that paint exposure increases the risk of asthma attacks among children because high levels of VOCs persist indoors for many weeks after painting. Children 1–15 years old visiting two of the University of Miami general pediatric clinics were screened for their history of asthma and paint exposure by interviewing their parents and/or guard-ians accompanying them to the clinic. They were also asked questions about asthma diagnosis, severity of asthma and allergies and their sociodemographics. The risk of asthma attack among asthmatic children was modeled with respect to paint exposure adjusting for potential confounders using multivariate logistic regressions. Of 163 children, 36 (22%) reported physician-diagnosed asthma and of these, 13 (33%) had an asthma attack during the last one year. Paint exposure was marginally significant in the univariate analysis (OR = 4.04; 95% CI = 0.90–18.87; p \u3c 0.1). However, exposed asthmatic children were 10 times more likely to experience an asthma attack than unex-posed asthmatic children (OR = 10.49; CI = 1.16–94.85, p \u3c 0.05) when adjusted for other risk factors. Given paint is one of the sources of indoor VOCs, multiple strategies are warranted to manage the health effects of VOC exposure from paint, including the use of zero-VOC water-based paint, exposure avoidance and clinical interventions
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